The core of LXD is a privileged daemon which exposes a REST API over a local unix socket
as well as over the network (if enabled).

Clients, such as the command line tool provided with LXD itself then do everything through that REST API.
It means that whether you're talking to your local host or a remote server, everything works the same way.

LXD isn't a rewrite of LXC, in fact it's building on top of LXC to provide a new,
better user experience. Under the hood, LXD uses LXC through liblxc and its Go binding
to create and manage the containers.

It's basically an alternative to LXC's tools and distribution template system
with the added features that come from being controllable over the network.

The current LTS is LXD 3.0 which is supported until June 2023 and gets frequent bugfix and security updates
but does not receive any feature addition.

Feature releases are pushed out every month or so and contain new features as well as bugfixes.
The normal support length for those releases is of about a month, or until the next one comes out.
Some Linux distributions may offer longer support for particular feature releases that they decided to ship.

Commercial support for LXD on Ubuntu LTS releases can be obtained from Canonical Ltd.